Strategic Buffer Layer Development for YBCO Coated Conductors

Abstract

We have developed a simplified buffer layer architecture for the rolling-assisted biaxially textured substrates (RABiTS) template approach. The overall purpose of this research is to enable potentially a low-cost, high throughput and high yield manufacturing processes for buffer fabrication and to gain fundamental understanding of the growth of buffer layers for RABiTS templates. This understanding is critical to the development of a reliable, robust, and long-length manufacturing process for second generation wires. In this study, efforts are being made to either reduce the number of vacuum deposited layers or to replace one or more of these vacuum deposited layers with a solution based layer. We have chosen Gd2O3 - ZrO2 system as a potential barrier layer for this study. We have deposited epitaxial Gadolinia Stabilized Zirconia (GSZ) (Zr1-xGdxOy; x = 0-1) films on 30-nm thick e-beam evaporated Y2O3 seeded Ni-W (3 at. %) (Ni-3W) substrates using a metal-organic decomposition (MOD) process. Detailed X-ray studies indicated that all of the MOD-GSZ layers were cube textured and both in-plane and out-of-plane lattice parameters increases linearly with increasing the Gd content. We have also developed process conditions for reactively sputter deposited epitaxial Gd2Zr2O7 (Gadolinium Zirconium Oxide (GZO); Zr1-xGdxOy (x = 0.5)) films on the e-beam evaporated Y2O3/Ni - 3W substrates. YBCO films with a critical current density Jc of 2.14 times 106 A / cm2 and 1.4 times 106 A / cm2 at 77 K and self-field were grown on the newly developed architectures of Gd2Zr2O7/Y2O3/Ni - 3W and Zr1-xGdxOy (x = 0.2)/Y2O3/Ni - 3W substrates, respectively using a pulsed laser deposition (PLD) process. This work promises a route for producing cost-effective simplified buffer architectures for the RABiTS-based YBCO coated conductors.